The invention is generally related to containers having a collapsible plastic bag containing fluid and means for dispensing this fluid from the bag. More specifically, the container bags often are filled with liquid which can be contaminated by air, and therefore the fluid must be dispensed from the bag without a substantial introduction of air.
A container presently becoming more widely used for dispensing fluids such as milk which deteriorate in contact with air consists of a thin-film plastic forming a bag within a cardboard box. The plastic bag is filled with the liquid and as the liquid is removed, the bag collapses within the box so that no air need enter the bag to replace the dispensed liquid and therefore no air contamination occurs. Presently post-mixed syrup for use in fountains, for example, in mixing soft drinks at a bar is held in a stainless steel container from which it is pumped to a dispensing nozzle where it is mixed with other ingredients. It is desired to substitute the plastic bag system referred to above for the stainless steel containers.
It is important that no air be introduced into this system for several reasons. First, air may be harmful to the pump. Secondly, the air dilutes the syrup which is dispensed in a measured mixing ratio with other ingredients in order to produce the soft drink. Thirdly, air can be detrimental to the fluid itself. It is not only important to be able to dispense the fluid without introducing air, but it is also advantageous for the container to be able to be re-sealed without introduction of air. This allows for changing the fluid container when only partially empty permitting its re-use at a later time. In the re-sealing, none of the fluid escapes to create a messy and unsanitary condition with, for example, syrup dripping from the container.
Many different types of containers and dispensing mechanisms for containers have been developed in the past. None, however, satisfy the requirements for a fluid dispensing system as described above.